1. Field of the Invention
This invention relates to an angle-adjustable hinge as a joint member with which an angle formed by members on one side and another side can be freely set.
2. Description of the Related Art
A legless chair having a back 15 and a seat 16 as shown in a perspective view of FIG. 1 is provided with a hinge between the back 15 and the seat 16 having angle-adjusting function to adjust an inclination angle of the back 15, namely, an angle-adjustable hinge A.
This conventional hinge is constructed as that a gear and a claw piece of a second arm on another side (the back 15 side) are held in a case portion of a first arm connected to one side (the seat 16 side) to restrict oscillation of the second arm in an extending direction (reclining direction of the back 15) to the first arm by engagement of the claw piece with the gear (refer to Japanese utility model publication No. 59-20118).
In the conventional hinge, the claw piece and teeth of the gear are large, and pitch of the teeth of the gear is rough because force working between the first arm and the second arm (force necessary to restrict the oscillation) is to be very large to support man's weight. That is to say, the claw piece and the gear can not be small because of necessary strength.
Therefore, the case portion for storing the claw piece and the gear becomes large, number of the teeth of the gear is small (the pitch is large), and fine adjustment is impossible for small number of angle change stages.
It is an object of the present invention to provide an angle-adjustable hinge with which the number of angle change stages is made large and the entire hinge is made small with small components.